Exchange rate is US$1 ~ JPY80, but that is not really relevant because I have to get a card from Japan anyways. Out of these setups, what would you suggest for a 2600k @ 4.5 + Z68 Extreme 4 + Corsair TX850 + 1080p screen? (i cannot tolerate noise and would overclock the cards as much as reasonable)

That Afox looks to be a nice vanilla card. If you're not going to OC as far as it goes, you can pick the 570 up (since it's limited by VRM). Otherwise, I'd try to find a reference 6950/6970 or a Twin-Frozr, which has a solid custom cooler on top of it. Or a pair to CF. BTW, you don't need to worry about microstuttering.

Great. Microstutter is a common myth, well at least for dual-GPU setups. "Microstutter" can only refer to skipping frames. People misinterpret it with CrossFire Scaling. As the second GPU will give more power, your frametime will decrease, which equates to more FPS, and less stuttering. So a dual-GPU setup is in fact likely to encounter less stutter than a single card. However, since you won't get perfect scaling in games, there'll be times the CF setup will underperform against a more powerful, single GPU. On the other times, you'll get good scaling and a constant, smooth action.

Well all I know is, there is some sort of stuttering related to multiGPUs because there doesn't seem to be a way to synchronize the frames. i.e. if one GPU lags for some reason, frames that should come later might come earlier and that constitutes stutter.

I just hope I won't see it in the games I play. I saw a lag while playing Crysis 2 maxed out with the high res texture pack. But it was not microstuttering IMO. Looked like the GPUs were running out of RAM as these cards are 1GB. (would have got the 2GB models I they were not expensive. Diff was like $40 per card)

Yeah, but that's only the situation with triple, and importantly Quad-GPU setups. It's a case of skipping frames between carrying the info overhead along each GPU. Other hand, if you go out of vRAM, it just lags down. And yep, Crysis 2 needs more vRAM with the DX11 patch. Have a look at this